If you are interested in further reading regarding otherkinity, then this is your place to get started!
The Otherkin Timeline: the full history of otherkinity, as opposed to my more shortened version of it.
A Timeline of the Fictionkin Community: otherkin history, with a focus on fictionkin.
The Elf Queen's Daughters and the Silver Elves: the activity of the Elf Queen's Daughters and the Silver Elves, who are early examples of otherkin.
From Fiction: forums, information, and more.
Alterhuman Archive: a collection of alterhuman-related information, writings, and creations.
The Chimeras Library: essays and information.
Nonhumanity and Nonsense: essays and a glossary.
Orion Scribner's site: a site for someone who has written essays, articles, and books on otherkin.
Wildpath Library: a resource hub for nonhumans, including essays, surveys, and academic articles.
AnOtherWiki: a wiki for the otherkin community.
Dreamhart: a more spiritually-focused site with articles, links, and other information.
ProjectShift: an informational site about therianthropy with resources for therians.
Therian Wiki: an expansive wiki for therians.
The WereLibrary: an index of writings, all about therianthropy.
Synpath FAQ: a FAQ about synpaths, by the coiner of the term.
What is copinglink?: an article about what copinglink is.
Otherkin theories and sources: exactly what it says on the tin.
Rani's 'kin for fun' tag: firsthand account of the problems with the 'kin for fun' community.